METAZOA INSECTA. 447 



nura. It also has the biting mouth parts of the general- 

 ized insects. But in addition to these structural features, 

 Corydalus has nine pairs of long branching filaments 

 extending from the sides of the abdomen, and seven pairs 

 of sponge-like masses also used for respiration (see No. 

 1132), or it may be to aid the animal in attaching itself 

 to the surface of stones at the bottom of swift-flowing 

 streams. 1 Besides these branchial organs the larva is 

 provided with the tracheae which its ancestors possessed, 

 and which are useful during the pupal stage that lasts 

 about a month and is spent in a cell in the earth under 

 some stone or log. The adult (No. 1 133, ; No. 1 134, 9 ) 

 is a giant among insects. The mandibles of the female 

 are used for obtaining and masticating food, while those 

 of the male are weapons and also clasping organs. The 

 wings expand six inches (Packard) but as the thoracic 

 segments which bear them are unconsolidated, we should 

 predict that the flight of the insect would be slow, and 

 this is the case. 



The wings have an open network of veins. The name 

 Neuroptera, meaning nerve and wing, was formerly given 

 to an order of insects whose typical fo'rm was the dragon- 

 fly, and the significance of the term is much more appar- 

 ent when we consider the fine network of veins peculiar 

 to the dragon-fly wing than it is when we examine the 

 Corydalus wing. Now, the dragon-flies are placed in an 

 order by themselves, the Odonata, and the name Neurop- 

 tera is retained for the Sialidae, Hemerobidae, and the 

 like, which pass through an indirect development. 



One of the interesting Neuroptera is the lace-winged 

 fly or aphis-lion, Chrysopa perla. The female has the 

 habit of fastening her eggs at the tip end of long stalks. 

 In order to do this she secretes from her abdomen a 

 drop of a tenacious substance which she draws out into a 

 thread; at the end of this thread she places a knob of 



1 Riley, Qth Rep. Benef. and Inj. Insects Mo., 1877, p. 128. 



